Online Viscometer - Online quality controlPrecise, compact, easy handling.


The online viscometer is used for continuous control of the melt viscosity of a production extruder. Two melt pumps with only one drive guarantee a permanent melt flow. The COLLIN Polytest Line measuring device is not only characterized by its compact design but also by flexibility and the closed material flow. Moreover, there is no waste production.

A bypass adapter takes melt out of the production extruder and guides it through a capillary. Along this capillary, the loss of pressure is measured. Then, the melt is returned into the extruder.

Via the differential pressure, rheological characteristic values of the material (e. g. iV value, MFR) can be determined. For a constant melt flow, in front and behind the capillary, a melt pump with common drive is provided. For the viscosity, besides the pressure, also the melt temperature is relevant. Therefore, the viscometer is controlled to the adjusted temperature and additionally, the melt temperature in front of the capillary is measured.


  • Precise, user-friendly
  • Cost-efficient, since there is only one drive motor for two pumps
  • Clear, simple display of the viscosity value
  • Low space requirement
  • Connection to each extruder, compounder and production extruder is possible


  • IV values from 0.4 – 1
  • MFR 1-200
  • Further designs on request

Monitoring of the melt viscosity at a production extruder

The information is displayed via an overview screen with set values, operating status and viscosity value. Alternatively, the measuring value trend can be displayed as graphic.


  • Plastic processing industry
  • Production companies
  • Recycling companies
Measuring capillaryØ 2 x 60 mm (standard), different capillaries available
Max. pressure build-up in front of the capillary350 bar
Melt pump throughput0.45 cm³/r
W x D x H120 x 193 x 540 mm

Software adjustment possibilities

Measuring temperature
Adapter temperature (as option, depending on the design)
Set-back temperature (standby)
Max. pressure
Pump speed